Issue #46: implement Python async client values errors and CLI

clients/python/src/mxgateway/errors.py

@@ -0,0 +1,157 @@
+"""Typed exception model for MXAccess Gateway Python clients."""
+
+from __future__ import annotations
+
+from typing import Any
+
+import grpc
+
+from .generated import mxaccess_gateway_pb2 as pb
+
+
+class MxGatewayError(Exception):
+    """Base class for client wrapper errors."""
+
+    def __init__(
+        self,
+        message: str,
+        *,
+        protocol_status: pb.ProtocolStatus | None = None,
+        raw_reply: Any | None = None,
+    ) -> None:
+        super().__init__(message)
+        self.protocol_status = protocol_status
+        self.raw_reply = raw_reply
+
+
+class MxGatewayTransportError(MxGatewayError):
+    """Transport-level gRPC failure."""
+
+
+class MxGatewayAuthenticationError(MxGatewayTransportError):
+    """Authentication failure reported by gRPC."""
+
+
+class MxGatewayAuthorizationError(MxGatewayTransportError):
+    """Authorization failure reported by gRPC."""
+
+
+class MxGatewaySessionError(MxGatewayError):
+    """Gateway session failure."""
+
+
+class MxGatewayWorkerError(MxGatewayError):
+    """Gateway worker process or protocol failure."""
+
+
+class MxGatewayCommandError(MxGatewayError):
+    """Command failure that preserves the raw protobuf reply."""
+
+
+class MxAccessError(MxGatewayCommandError):
+    """MXAccess HRESULT or status failure."""
+
+
+def map_rpc_error(operation: str, error: grpc.RpcError) -> MxGatewayTransportError:
+    """Map a generated gRPC exception to the client exception hierarchy."""
+
+    code = error.code() if hasattr(error, "code") else None
+    details = error.details() if hasattr(error, "details") else str(error)
+    message = f"{operation} failed: {details}"
+
+    if code == grpc.StatusCode.UNAUTHENTICATED:
+        return MxGatewayAuthenticationError(message)
+    if code == grpc.StatusCode.PERMISSION_DENIED:
+        return MxGatewayAuthorizationError(message)
+
+    return MxGatewayTransportError(message)
+
+
+def ensure_protocol_success(
+    operation: str,
+    protocol_status: pb.ProtocolStatus | None,
+    raw_reply: Any | None = None,
+) -> Any | None:
+    """Raise typed gateway errors for non-OK protocol statuses."""
+
+    code = (
+        protocol_status.code
+        if protocol_status is not None
+        else pb.PROTOCOL_STATUS_CODE_UNSPECIFIED
+    )
+
+    if code in (
+        pb.PROTOCOL_STATUS_CODE_OK,
+        pb.PROTOCOL_STATUS_CODE_MXACCESS_FAILURE,
+    ):
+        return raw_reply
+
+    message_text = protocol_status.message if protocol_status else ""
+    message = f"{operation} failed: {message_text or pb.ProtocolStatusCode.Name(code)}"
+
+    if code in (
+        pb.PROTOCOL_STATUS_CODE_SESSION_NOT_FOUND,
+        pb.PROTOCOL_STATUS_CODE_SESSION_NOT_READY,
+    ):
+        raise MxGatewaySessionError(
+            message,
+            protocol_status=protocol_status,
+            raw_reply=raw_reply,
+        )
+
+    if code in (
+        pb.PROTOCOL_STATUS_CODE_WORKER_UNAVAILABLE,
+        pb.PROTOCOL_STATUS_CODE_TIMEOUT,
+        pb.PROTOCOL_STATUS_CODE_CANCELED,
+        pb.PROTOCOL_STATUS_CODE_PROTOCOL_VIOLATION,
+    ):
+        raise MxGatewayWorkerError(
+            message,
+            protocol_status=protocol_status,
+            raw_reply=raw_reply,
+        )
+
+    raise MxGatewayCommandError(
+        message,
+        protocol_status=protocol_status,
+        raw_reply=raw_reply,
+    )
+
+
+def ensure_mxaccess_success(operation: str, reply: pb.MxCommandReply) -> pb.MxCommandReply:
+    """Raise `MxAccessError` when MXAccess returned HRESULT or status failure."""
+
+    status = reply.protocol_status
+    if status.code == pb.PROTOCOL_STATUS_CODE_MXACCESS_FAILURE:
+        raise MxAccessError(
+            _mxaccess_message(operation, reply),
+            protocol_status=status,
+            raw_reply=reply,
+        )
+
+    if reply.HasField("hresult") and reply.hresult < 0:
+        raise MxAccessError(
+            _mxaccess_message(operation, reply),
+            protocol_status=status,
+            raw_reply=reply,
+        )
+
+    for mx_status in reply.statuses:
+        if mx_status.success == 0:
+            raise MxAccessError(
+                _mxaccess_message(operation, reply),
+                protocol_status=status,
+                raw_reply=reply,
+            )
+
+    return reply
+
+
+def _mxaccess_message(operation: str, reply: pb.MxCommandReply) -> str:
+    status_text = reply.protocol_status.message or "MXAccess command failed"
+    hresult = reply.hresult if reply.HasField("hresult") else None
+    return (
+        f"{operation} failed: {status_text}; "
+        f"session={reply.session_id}; correlation={reply.correlation_id}; "
+        f"hresult={hresult}; statuses={len(reply.statuses)}"
+    )